Cathead



P. M. REA

Oct. 3, 1939.

CATHEAD 2 Sheets-Sheet l aux Filed Feb. 20, 195? Rm Y I m H 0 MM 5 m IP/Ii/ BY P. M. REA

Oct. 3, 1939.

CATHEA-D Filed Feb. 20, 1937 2 Sheets-Sheet 2 INVENTOR gimp M fi Q.

A TORNEY Patented Oct. 3, 1939 E ATENT OFFlCE GATHEAD Philip M. Rea,Oklahoma City, Okla.

Application February 20, 1937, Serial No. 126,841

7 Claims.

This invention relates to cat-heads used in connection with thedraw-works of a well dril1- ing rig for providing the power required inbreaking the tool joints in a string of drill pipe or the like.

The principal object of the invention is to provide a cat-head with asimple and reliable means for effecting operative connection anddisengagement of the driven element with the countershaft of thedraw-works.

It is also an important object of the invention to provide a cat-headconstruction which permits of ready assembly and secure retention of theparts.

Further objects of the invention are to provide an improved means formanually effecting engagement of the latch-dog with a driven quill aboutwhich the driven element of the cat-head is rotatably mounted; toprovide a cat-head construction whereby the driving forces are exertedin the direction of rotation so that there are no end thrusts impartedto the driving and driven elements; and to provide for engaging andtripping of the latch-dog without resultant ill effects on thedraw-works.

In accomplishing these and other objects of the invention, ashereinafter pointed out, I have provided improved details of structure,the preferred form of which is illustrated in the accompanying drawings,wherein:

Fig. 1 is a perspective view of a portion of a draw-works equipped witha cat-head embodying the features of the present invention.

Fig. 2 is an enlarged detail section through the cat-head illustratingdriving engagement of the latch-dog with the driving quill.

Fig. 3 is a vertical section through the cathead on the line 33 of Fig.2, illustrating the latch-dog in disengaged position but ready to bemoved into position to be engaged by a latchdog engaging face of thequill.

Fig. 4 is a similar section showing the latchdog in engaged position andmoving toward the point where the latch-dog is ordinarily disengagedfrom the quill.

Fig. 5 is a section on the line 5-5 of Fig. 2 illustrating the latch-dogcontrol rollers entering the return track to hold the latch-dog out ofdriven engagement with the quill during reverse rotation of the drivenelement.

Fig. 6 is a detail view of the latch-dog, one of the control rollersbeing shown in section.

Fig. 7 is a detail perspective view of the housing sections shown indisassembled spaced relation to better illustrate the track-waystherein.

Fig. 8 is a detail perspective view of the driving quill, the drivenelement, the latch-dog and the spool which cooperates with the quill inretaining the driven element.

Referring more in detail to the drawings: 5'

i designates a draw-works including jack posts 2 mounted on a derrickplatform 3 and support ing the usual counter-shaft 4 and line shaft 5from which the rotary drilling tools are operated as in conventionalpractice. The end of the line shaft 5 projects beyond the outer post 2to mount a cat-head 6 which is constructed in accordance with thepresent invention.

The cat-head includes a quill I having a sleevelike body 8 provided witha longitudinal bore 9 to snugly engage the projecting end of the shaft5. The quill is keyed to the shaft 5 by means of a spline I engaging ina keyway H formed in the side of the shaft and in a registering keyrecess E2 that is formed in the inner face of the sleeve-like body, asbest shown in Figs. 2 and 3. The quill is of suflicient length toaccommodate a driven element M which operates a jerk line presentlydescribed and to mount a spool l that is used in certain of the drillingoperations and which cooperates with the quill in retaining the drivenelement. The outer periphery of the quill is shaped to provide anannular stop flange M3 on the end adjacent the post 2, and spaced fromthe stop. flange a distance corresponding to the width of the drivenelement is an annular shoulder I! that is formed by reducing the outerdiameter of the quill to correspond to the inner diameter of the spool.Formed in the outer surface of the quill, at a point midway between theflange l6 and the shoulder H. is a series of arcuate recesses or groovesl8 having bottoms !9 extending from a point on the periphery of thequill to a spaced point inset from the surface of the quill to provide alatch-dog engaging face 29. The side Walls 2! and 22 of the recessesextend substantially parallel and are spaced apart a distance slightlygreater than the width of the latch-dog, later described.

The driven element includes a collar 23 having a central internal band24 of a diameter to freely and rotatably engage the notched portion ofthe quill and having its ends counter-bored to provide annular bearingrecesses 25 and 26 in which are mounted sets of roller bearings 21 and28 to reduce tendency of the collar to drag upon the quill when thecollar is disengaged from driving relation therewith as later described.The outer periphery of the bushing is provided 55 with an annular groove2& separating annular bearing faces 36 and 3H which engage in bushings32 and 33 located within the sections as and 35 of a housing 36.

Formed in the groove 29 and extending completely through the wall of thecollar 23 is a slot 3'! in which a latch-dog 38 is adapted for movementas later described. The slot 3'5 includes a portion 39 of slightlygreater width than the groove 29 to allow free movement of the latchdoglug. The latch-dog is best illustrated in Fig. 8 and includes asubstantially rectangular lug portion ill that extends freely throughthe portion 39 of the slot 3i and is adapted to engage in the respectivenotches of the quill to effect driving engagement with the faces 2%] aslater described. The latch-dog includes a tail portion il pivotallymounted within the narrow portion of the slot 3? on a pivot pin t2 thatextends through an opening &3 in the tail portion of the latch-dog andhas its ends mounted in openings 44 formed in the sides of; the slot 31as best illustrated in Fig. 8.

Carried by the latch-dog at a point directly above the lug All, arelaterally extending spindles 45 and 46 carrying rollers ll and 58.Formed in the latch-dog is a tapered socket :9 in which one end of ajerk line 56 is babbitted as shown at 5| in Fig. l. The jerk lineextends over the tail portion of the latch-dog and operates within thegroove 29. Its opposite end is adapted to be connected with a wrench onthe upper section of a tool joint (not shown) as in well known practice.

The housing sections 3t and 35 are of substantially the sameconstruction and include annular web or disk-like wall portions 52 and53 having axial openings 54 and 55 of suitable diameter to pass freelyover the quill and to accommodate the bushings 32 and 33, previouslymentioned. Formed in the web portions 52 and 53, in concentric relationwith the bushed open ings, are inner and outer arcuate track-ways 5651and 58-59 which are connected at their respective ends by transfergrooves Eli-6| and 6263 respectively. The inner groove conforms in widthto the diameter of the rollers 41 and 48 on the latch-dog and are of adepth to freely accommodate the length of the rollers. The outer groovesare of similar depth but may be of greater width than the diameter ofthe rollers as shown in Fig. 5. The track-ways are thus separated byarcuate flanges 64 and 55 having inner edges 66 and 67 spaced apart toforman annular pathway through which the latch-dog is adapted to move aslater described. The ends SSS-69 and lll'll of the flanges are slightlyrounded at their juncture with the track-ways to facilitate transfer ofthe rollers from, one groove to the other. The transfer grooves 6i and63 are rounded, as at T2 and 13, to provide throw-out portions at theterminal ends of the inner track-ways to guide the rollers into theouter track-way for return of the driven collar under pull of the jerkline as later described.

In order to transfer the rollers from the outer groove to the innergroove, and thereby effect engagement of the lug All with one of therecesses of the quill, I provide an elevating device including a lever il extending through slots '15 and 16 provided in the outer annularflange of the housing sections as best shown in Fig. 7. The lever ispivoted on a pin Ti that is carried by spaced ears l8 and ill on therespective housing sections. The inner end 8E3 of the lever projects asufficient distance within the housing to adapt it for movement entirelyacross the width of the outer track-ways and slightly within the spaceat the ends E59 of the flanges 64 and 655, as shown in Figs. 4 and 5.The outer end 8! of the lever is connected with a control line 82whereby the lever may be actuated to eifect transfer of the rollers onthe dog from the outer track to the inner track and thereby move the luginto position to be engaged by one of the latch engaging faces of thequill. The outer flanges are of suflicient depth to close the spacecircumferentially of the latch-dog passage, however, the portionsthereof adjacent and between the terminal ends of the track-ways arenotched as at 33 and B4 to provide a slot through which the jerk line ispassed, as clearly shown in Figs. 1, 3 and 4, for connection with thewrench as above mentioned.

The housing sections are provided with pairs of radial lugs 85 and 85through which fastening devices, such as bolts 3?, are extended tosecure the sections together. The section 34 has an attaching flange 88whereby the housing is secured to the post 2 to prevent rotationthereof.

The spool l5 includes a sleeve-like body 89 having an inner diameter topass over the reduced portion of the quill as shown in Fig. 2, and iskeyed thereto by a spline 9Q engaged in registering grooves formedwithin the outer periphery of the quill and in the inner diameter of thespool. The spool has an annular flange 9! abutting the annular shoulderl? and which cooperates with the flange IE to retain the roller bearingsas shown in Fig. 2. In order to prevent lateral displacement of thespool, the outer end 92 is recessed to accommodate a plate 93 that issecured to the end of the quill by fastening devices, such as cap screws94, extending through openings 95 in the plate and into threaded socketsformed in the end of the quill as shown in Fig. 8.

In assembling a oat-head constructed as described, the key it isinserted in the recess !2 of the quill and the quill is slid over theprojecting end of the shaft 5 so that the key enters the groove of theshaft. The housing section 34 is then sleeved over the quill so that theouter face of the web portion thereof engages the flange it. The drivenelement carrying the latch-dog is then sleeved over the quill and theroller bearings inserted in the bearing recesses 25 and 2t. When thedriven element is properly assembled, the annular bearing portion 3E3thereof engages within the bushing of the housing section 3 3 so that itis rotatably mounted therein. The jerk line is extended around thedriven element so that it lies within the groove 28. The roller i! islocated in the transfer groove fill of the housing section M, forexample as shown in Fig. 3. The other housing section is then sleevedover the bearing portion 3! of the driven element whereupon the bolts8'1 are passed through the ears and 86 to secure the sections together.The flange 83 of the section ta l is then attached to the post 2 toprevent relative rotative movement of the housing. The lever "it is thenapplied so that the inner end thereof engages under the latch-dog asshown in Fig. 3, and connected with the control line 82. The spool isthen sleeved over the outer end of the quill after which the key 90 isinserted to secure the spool in driving relation therewith. Afterinsertion of the key the plate 93 is applied to the end of the qull tocomplete the assembly.

In using a cat-head assembled as described, the normal position of thelatch-dog is as illustrated in Fig. 3, with the head of the latch-dogresting upon the forward end 80 of the lever 14, and with the rollerslocated in the transfer passages 62. In this position the lug on thelatch-dog is out of the path of travel of the latch engaging faces 20.The quill therefore rotates freely within the driven element and thedriven element remains stationary due to the fact that the friction ofthe surfaces 30 and 3| with the housing bushings is great enough toresist any tendency for the driven element to rotate. Movement of thedriven element is also resisted by the jerk line. After the jerk linehas been connected with the wrench used in breaking the tool joint, thelatch-dog is rendered effective by pulling on the cable 82 to cause theforward end of the lever 14 to raise the latchdog into position wherethe rollers 41' and 43 will enter the inner track-ways. In this positionthe lug on the latch-dog is moved into peripheral contact with the quilland into one of the recesses to be engaged by the latch dog engagingface 20. .The quill therefore picks up the driven member through itsconnection with the latch-dog, causing it to rotate in a counter-cloclowise direction, Fig. 3. Rotation of the driven element causes the jerkline to wrap about the periphery of the groove 29 as shown in Fig. 4 toexert a pull on the wrench. The rollers 41 and 48, moving in the innercam groove, keep the lug of the latch-dog in engagement with the quillso that the clutching engagement is maintained until the rollers engagethe rounded portions 13 of the transfer grooves 6! and 63. As soon asthe rollers engage these portions of the grooves, they are cammedoutwardly to lift the lug out of engagement with the quill and to guidethe rollers into alignment with the outer trackways, as shown in Fig. 5.When a pull is exerted on the jerk line, the driven member is caused torotate in a clockwise direction (Fig. so that it is returned to itsstarting point, as illustrated in Fig. 3. Due to the fact that therollers remain in the outer track-ways the latch-dog is held out ofdriving engagement with the quill. As soon as the rollers contact thelever I4, they cause the forward end of the lever to swing downwardly,restoring the lever to its original position so that the latch-dog canbe again lifted thereby into engagement with the driving portions of thequill.

From the foregoing it is obvious that I have provided a cat-headconstruction whereby the driving forces are all exerted in the directionof rotation so that there are no end thrusts imparted to the driving ordriven elements. The engagement of the latch-dog with the quill, andalso the trippingof the latch-dog from engagement with the quill, areaccomplished without shock and resultant ill eifects on the draw-works.The pull on the line is also applied directly into the shaft and at apoint close to the shaft support on the draw-works.

What I claim and desire to secure by Letters Patent is:

1. In combination with a rotatable driving member having latch-dogengaging portions and bearing races on the respective sides of saidengaging portions, a driven member including a collar rotatably mountedon the driving member and having races cooperating with the first namedraces, antifriction bearings for said races, a latchdog movablysupported on the driven member and adapted to engage the latch engagingportions on the driving member, a housing for said driven member, meansin the housing forming communicating primary and return trackways,

means for automatically shifting the latch-dog from the primary to thereturn track-way and disengaging the dog from the driving member, andmanually operable means at the opposite end of the track-ways forreturning the latch-dog to the primary track-way and engaging said dogwith the driving member.

2. In combination with a rotatable driving member having latch-dogengaging portions, a driven member including a sleeve-like bodyrotatably mounted on the driving member, a latchdog movably supported onthe driven member and adapted to engage the latch engaging portions onthe driving member, a housing for said driven member and having innerand outer track-ways interconnected by transfer-ways, guide means on thelatch-dog operable in said ways to respectively maintain engagement ofthe latch-dog with the driving member during rotation of the drivenmember by the driving member and disengagement of the latch-dog uponreverse rotation of the driven member, and means for effecting transferof the guide means from one of the track- Ways to the other to effectshifting of the latchdog into engagement with the engaging portions ofthe driving member.

3. In combination with a rotatable driving member having latch-dogengaging portions, a driven member including a sleeve-like bodyrotatably mounted on the driving member, a latchdog movably supported onthe driven member and adapted to engage the latch engaging portions onthe driving member, a housing for said driven member and having innerand outer track-ways interconnected by transfer-ways, a roller on thelatch-dog operable in said track-ways to respectively maintainengagement of the latch-dog with the driving member during movement ofthe driven member by the driving member and disengagement of said dogduring reverse movement of the driven member, means for effectingtransfer of the roller from one of the track-ways to the other forshifting the latch-dog into engagement with the engaging portions of thedriving member, and means adapted for engagement by the roller toautomatically disengage the latchdog.

4. In combination with a rotatable driving member having latch-dogengaging portions, a driven member including a sleeve-like bodyrotatably mounted on the driving member, a latch-dog movably supportedon the driven member and adapted to engage the latch engaging portionson the driving member, a housing for said driven member, having innerand outer track-ways interconnected by transfer-Ways, guide means on thelatch-dog operable in said ways to respectively maintain engagement ofthe latch-dog with the driving member during movement of the drivenmember by the driving member and disengagement therefrom during reversemovement of the driven member, means for effecting transfer of the guidemeans from one of the trackways to the other for shifting the latch-doginto engagement with the engaging portion of the driving member, meansfor engagement by the guide means to disengage the latch-dog, and a jerkline connected with the driven member, adapted to wind upon said drivenmember during driving thereof by the driving member and whereby thedriven member is rotated reversely upon unwinding of the line.

5. In combination with a rotatable driving member having latch-dogengaging portions, 3.

driven member including a sleeve-like body rotatably mounted on thedriving member, a latchdog movably supported on the driven member andadapted to engage the latch engaging portions on the driving member, ahousing for said driven member and having inner and outer trackwaysinterconnected by transfer-Ways, a roller on the latch-dog operable insaid ways to respectively maintain engagement and disengagement of thelatch-dog with the driving member, means for efiecting transfer of theroller from one of the grooves to the other to move said latch-dog intoengaging relation with said engaging portions of the driving member,means engageable by the roller to disengage the latchdog, and a jerkline connected with the latch-dog and adapted to be wound on the drivenmember when the latch-dog is engaged with the driving member and to beunwound from the driven mem ber to return the driven member to itsoriginal position.

6. In combination with a driving member ineluding a rotatable drivingshaft, a quill sleeved on the shaft and having latch-dog engagingportions, means fixing the quill to the shaft, a driven member sleevedon the quill and having a circumferential opening, a jerk line, alatch-dog connected to the jerk line having a tail portion pivoted insaid opening, said tail portion being adapted to cooperate with thedriven member to support the jerk line when the latch-dog is engagedwith the quill, track-ways spaced at different distances from thedriving member for maintaining engagement and disengagement of thelatch-dog relatively to said engaging portions of the driving member,means for effecting engagement of the latch-dog with said engagingportions of the driving member to drive the driven member, and means foreffecting automatic release of the latch-dog.

7. In combination with a rotatable driving member having latch-dogengaging portions, a driven member rotatable about the axis of thedriving member, a latch-dog movably mounted on the driven member andadapted for engaging said engaging portions of the driving member, amember surrounding the driving member forming interconnected inner andouter track-Ways, and a jerk line connected with the latch-dog adaptedto Wind on the driven member, guide means on the latch-dog adapted fortravel in one track-Way when the latch-dog is engaged and in the othertrack-Way when the latch-dog is disengaged, and means at the ends of thetrackways for shifting the guide means between the track-ways and thelatch-dog to and from engagement with the driving member.

PHILIP M. REA.

